"""
    Copyright (C) 2009  Andrew Stanton

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

"""
import lxml.etree as etree
import re

def _join(x):
    """
    Recursive string join for nested lists.
    """
    if isinstance(x, list):
        return ''.join([_join(i) for i in x])
    return x

def text(node):
    """
    Returns the joined string of all text nodes under the node.
    """
    if isinstance(node, etree._ElementStringResult):
        return node
    elif isinstance(node, etree._Element):
        return _join(node.xpath('.//text()'))

_dollarParse = re.compile('\$\d+(\.\d{2})?')

def dollars(node):
    """
    Extracts a dollar amount from text.
    """
    txt = text(node)
    try:
        return _dollarParse.search(txt).group()
    except:
        return None
